1. Field of the Invention
The invention is directed to: ultrasonic systems and methods for detecting flaws in tubular members; in certain particular aspects, to such systems and methods that are automatic and which accurately detect flaws near or at the ends of a tubular member such as pipe, tubing, casing, or other oil field tubulars; and, in certain aspects, to systems and methods for detecting defects in welds in, on, or between tubular members.
2. Description of Related Art
Flaws and defects in tubular members can result in the failure of the tubulars. Replacement or repair of a defective tubular can be time-consuming and expensive. In the oil and gas industries, tubular members used in drilling and other oil field operations are examined before use to detect and locate defects. Often a defect can be removed and the tubular used for its intended purpose. In other cases, the defect cannot be fixed and the tubular is rejected. Whether the tubular member can be used is based on characteristics of a defect, e.g. size, shape, location and orientation.
In some cases, defects located on a surface (interior or exterior) of a tubular can be visually characterized and examined to determine whether removal of the defect is necessary and possiblexe2x80x94and whether removal is feasible by grinding or other means; but often such visual examination of a defect is not accurate or is not possible.
Certain prior art ultrasonic inspection devices have used sonic beams to locate defects in tubular members. In certain systems the apparatus employed uses a piezoelectric crystal or crystals, each of which produces ultrasonic vibrations in response to the application of a voltage. Such systems often use a method in which a crystal is held in a position relative to the pipe surface to transmit a short duration sonic wave pulse of beamed energy into the wall of the pipe at an angle such that a flaw or discontinuity in the pipe causes the waves to be reflected back and produce a voltage response in the crystal, which is then de-energized immediately following the pulsed emission of a sonic wave so that reflected waves can be received during the de-energized periods to produce a corresponding electrical signal which may be analyzed for determining the nature and location of flaws. For example, U.S. Pat. No. 4,217,782 describes an ultrasonic inspection device for inspecting tubular members for the oil and gas drilling industries that employs two pairs of line-focused transducers that transmit sonic beams having a rectangular beam cross-section of about xc2xe inch in length. A first pair of the transducers transmits sonic beams longitudinally into the member to detect transverse defects. The second pair transmits sonic beams transversely into the member to detect longitudinal defects. The transducers in each pair transmit sonic beams in opposite directions. Two additional transducers monitor the wall thickness of the tubular member. Sonic beams transmitted longitudinally and transversely are used for the inspection of tubular members since defects are visible to only one or the other. Some flaws and defects are invisible to both longitudinally and transversely transmitted sonic beams. In certain prior art systems, the ultrasonic inspection device of U.S. Pat. No. 4,217,782 has been modified to include four spot-focused transducers that transmit sonic beams having a circular beam cross-section obliquely through a tubular member and a pair of transducers that transmit in opposite directions has been used to detect defects in tubular members as described in U.S. Pat. No. 3,289,468 since a given defect may be invisible to a transducer looking at it from one direction and visible to a transducer looking at it from the opposite direction.
In order to characterize a defect for size, shape, and orientation sonic beams are, in certain prior art systems, transmitted from several different directions followed by the receiving of beams reflected from the defect. As described in U.S. Pat. No. 3,332,278, reflected beams from one transducer have been received by several transducers to detect some of the defects.
U.S. Pat. No. 4,718,277 discloses an ultrasonic inspection device having an array of opposing transducers that longitudinally, transversely, and obliquely transmit sonic beams through tubular members having a range of diameters such that refracted beams meet on the inner surface of the members. Alternate halves of the array of transducers transmit and receive sonic beams reflected from defects in the tubular members using both the pulse-echo and pitch-catch methods.
U.S. Pat. No. 5,007,291 discloses ultrasonic inspection apparatus with centering means for tubular members that has pipe inspection apparatus with transducers for transmitting pulsed beams of ultrasonic energy longitudinally, transversely and obliquely into the wall of the pipe for detection of flaws. The apparatus includes a motor driven chuck for rotating the transducers about the a pipe and a motor driven roller for axial movement of the pipe whereby the transducers move in a helical scanning path. A control system maintains the axes of the pipe and circle array of transducers in coincidence and with hydraulic controls maintains each transducer at fixed distance to the pipe for sonicly coupling thereto by a flowing liquid whereby a shear wave is generated by each beam in the tubular wall. The transducers comprise multiple pairs, the members of which are diametrically opposed and transmit in opposite directions, for transmitting longitudinally at angles of 12 degrees, 27 degrees and 42 degrees to the pipe axis both clockwise and counterclockwise with one transducer of each pair disposed to transmit forward and the other reverse. For longitudinal flaws, one transducer of a pair transmits transverse clockwise and the other transverse counterclockwise. All transducers which transmit in a given direction are arrayed in the axial direction of the pipe. Pulsers simultaneously and repetitively energize and de-energize all forward transmitting transducers and after each such transmission pulsers simultaneously and repetitively energize and de-energize all reverse transducers. Reflection signals of predetermined strength are recorded and activate an alarm. A compressional wave transducer for determining wall thickness is included.
U.S. Pat. No. 5,313,837 discloses an ultrasonic thickness gage for pipe, which in certain aspects is a compact ultrasonic tester involving rotating sensors. A processor rotates with the sensors so that the output signal of the processor goes through slip rings, rather than to output signal of the sensors. A spraying system is incorporated in conjunction with rollers. The rollers take the applied spray on the pipe surface and paint a film on the outer pipe surface to allow a good contact for meaningful results. A floating shoe is provided for holding each sensor against the pipe wall. The sensors are biased into contact with the pipe surface and the machine can handle different diameters of pipe. By controlling the pipe speed of advance and the rotational speed of the sensors, a large percent coverage of the pipe wall is assured. The machine is compact and can be installed behind existing electromagnetic/gamma testers without major modifications to pipe-testing facilities.
U.S. Pat. No. 5,585,565 discloses a method for the ultrasonic inspection of pipe and tubing and a transducer which has an elastic membrane used to form a reservoir of ultrasonic fluid coupled to ultrasonic transducers with the membrane conforming to the surface of the tubing being inspected. Guide wheels maintain the membrane out-of-contact with the tubing during relative rotational movement of the assembly and tubing during inspection. Water is introduced between the membrane and the tubing to provide ultrasonic coupling of the tubing to the transducers through the fluid of the reservoir. Each of the patents mentioned above is incorporated fully herein in its entirety for al purposes.
Known automated ultrasonic systems for detecting flaws and defects in tubulars have been unable to adequately, accurately, and correctly detect inner surface defects relatively near the ends of the tubular member, e.g., within two feet or within eighteen inches of the ends up to the end boundary surface. For example, about eighteen to twenty four inches of the length of a thirty foot casing, ten and three-fourths inches in diameter, is often not accurately examined by certain automated prior art systems. The ends of such tubulars are often examined manually with portable electromagnetic or ultrasonic testing equipment in a time-consuming process. In various prior art systems the signals from the ends of the tubulars are not accurately distinguished from signals reflected from defects near the ends of the tubulars. This inability to distinguish and differentiate these signals renders these systems and methods inadequate for inner surface defect detection near the tubulars"" ends.
There has been a need for an ultrasonic inspection device that is capable of correctly and efficiently detecting and characterizing flaws and defects in tubular members and for such systems and methods that can do this for inner surface defects near or at the ends of the tubulars. There has long been a need for systems and methods for detecting defects in welds in, on, or between tubulars, e.g., but not limited to, the examination of girth welds of tool joints.
The present invention, in certain embodiments, discloses a system for detecting defects in tubular members which is capable of examining almost all of the entire length of the tubular; and, in certain aspects, which can accurately detect flaws including inner surface defects in substantially all of a tubular""s length and near or at its ends. In certain aspects this is accomplished with a system that nullifies, cancels, or ignores information from a signal reflected from a tubular end (or signals)xe2x80x94i.e. other than a signal or signals related to inner surface defectsxe2x80x94transmitted to and reflected from the tubular. In many instances a signal reflected from a tubular end is misinterpreted as, is not easily distinguishable from or is indistinguishable from a signal reflected from an inner surface defect near a tubular end and such a signal often cannot be accurately analyzed to determine whether there is a defect near the tubular end. A misinterpretation of such a signal can also result in a false indication of an inner surface defect.
In certain embodiments according to the present invention, signal information related to a signal reflected from the end of the tubular is used by an analyzing apparatus to determine the distance from ultrasonic transducers to the end of the tubular toward which the transducers are moving, but not for outer surface (outer diameter or xe2x80x9cO.D.xe2x80x9d) flaw detection; and, at the same time, the system does send and receive signals for the examination of the inner surface (inner diameter or xe2x80x9cI.D.xe2x80x9d) of the tubular member relatively near its end. By knowing the distance from the ultrasonic transducer(s) to the end of the tubular member, once the tubular""s outer surface has been examined, signals other than those related to examination of the inner surface and determining the distance to the tubular end can be ignored.
In certain aspects a system according to the present invention employs a transducer mount or xe2x80x9cshoexe2x80x9d that has a plurality (two, three, four, five or more) of ultrasonic transducers each of which can emit a beam that is reflected back to a receiving (xe2x80x9clisteningxe2x80x9d) transducer. In one aspect the reflected beams pass through a single beam passage area of the shoe for receipt by one of the transducers which is not in a beam-emitting mode (a xe2x80x9clisteningxe2x80x9d mode).
In one embodiment a shoe according to the present invention has a waveguide support for transducers that is made of Lucite (trademark) plastic or of similar plastic (or of low loss ultrasonic material). Multiplexe2x80x94e.g., two, three, four or fivexe2x80x94transducers are mounted relatively close to each other. Each transducer is mounted at a prescribed angle so that, in certain aspects, all reflected beams pass through the single beam passage area of the waveguide and are directed back to one of the transducers. In certain aspects such a system may also have one, two or more transducers located apart from the plastic waveguide support for examining the wall thickness of the tubular being studied. Alternatively, the wall-thickness transducer(s) may also be supported by the plastic waveguide support. Optionally a wear member may be mounted adjacent the plastic waveguide support and between it and a tubular for contacting the outer surface of the tubular being examined. The wear member may be a plate with a curved surface corresponding in shape to the curved outer surface of the tubular; it may be a flexible member made of flexible rubber, plastic, or similar material; or it may be an inflatable member such as a bladder or balloon whose contents (e.g. water that acts aa a waveguide) is adjusted to provide a shape that corresponds to the shape of the tubular. Fluid inlet(s) and outlet(s) in the shoe (e.g., but not limited to, in the plastic waveguide support or a mount in which the plastic waveguide support is held) provide fluid to the space between the wear member and the pipe being inspected so that there is no air in this space to impede transmission of the ultrasonic beams. Typical fluids for this include water, silicone, oil, and/or glycol. With a plastic waveguide the angle of refraction of the material is typically about 35.8 degrees. With systems in which the ultrasonic beams are transmitted through water, the angle of refraction is typically about 18.8 degrees.
In certain systems and members according to the present invention a weld on, in or between tubular members is inspected. In one particular embodiment a girth weld (e.g. welding a tool joint to another piece of pipe) is inspected for flaws. In one aspect such a system is automated so that a welded tool joint is rotated adjacent a transducer mount with one, two, three, four, five or more. The transducer mount is moved axially along the length of the joint as it rotates radially so that the entire weld is inspected. Any suitable apparatus for moving the transducer mount adjacent the joint may be used. In one particular aspect the mount is moved continuously until it is adjacent a weld portion; then optionally the mount is moved so that in a position immediately past the weld and the mount is held stationary there while the joint continues to rotate radially adjacent the transducersxe2x80x94thus insuring that the entire weld is inspected and the weld thickness past the weld is examined. Alternatively, the transducer mount is moved along the entire joint length in pre-set incremental steps and the final step is of sufficient temporal duration that the joint continues to rotate through the final step duration so that the wall thickness of the entire weld is inspected. By purposefully moving an ultrasonic transducer apparatus very near or past a weld, the entire weld is subjected to a full ultrasonic beam width.
It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:
New, useful, unique, efficient, nonobvious systems and methods for detecting defects in tubular members such as pipe, casing, tubing, and other tubulars;
Such systems and methods which can effectively and efficiently inspect nearly all of the length of tubular members, etc. relatively near (e.g. within a few millimeters or within an eighth of an inch) the ends thereof for both outer and inner surface defects;
Such systems and methods which accurately distinguish and differentiate an I.D. flaw detection beam reflected from an inner surface defect near a pipe end from a pipe-end-reflected beam;
Such systems and methods which ignore information related to a signal from a pipe-end-reflected beam and/or which nullify or cancel such a beam so that it is not confused with or misinterpreted as a near-pipe-end inner-surface-defect-reflected beam;
New, useful, unique, efficient and nonobvious systems and methods with single beam passage areas for all of a plurality of ultrasonic beams from a plurality of transducers used for tubular defect detection; and
New, useful, unique, efficient and nonobvious systems and methods for inspecting welds in, on, or between tubular members and for, in one particular aspect, inspecting entire girth welds of tool joints; and
Such systems and methods in which an ultrasonic transducer apparatus is positioned very near or past a weld so that the weld is subjected to the full beam width of an ultrasonic beam, which in one aspect is done by moving the ultrasonic transducer apparatus in step-wise manner adjacent the weld.
Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures and functions. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.
The present invention recognizes and addresses the previously-mentioned problems and long-felt needs and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one skilled in this art who has the benefits of this invention""s realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent""s object to claim this invention no matter how others may later disguise it by variations in form or additions of further improvements.